U.S. President Barack Obama has signed a law that bars an Iranian diplomat from serving as an envoy to the United Nations.

The legislation is aimed at blocking Hamid Abutalebi, whom the U.S. alleges was involved in the 1979 seizure of the U.S. embassy in Tehran.

The law signed by Mr. Obama Friday bars anyone from entering the United States as a U.N. representative if they are suspected of engaging in espionage or terrorist activity and may pose a threat to U.S. national security.

Last week, the U.S. denied a visa to Abutalebi, who was Iran's pick as U.N. representative.

Abutalebi was a member of the Muslim student group that held 52 American diplomats hostage for 444 days after taking over the U.S. embassy. He says his involvement with the group was limited to translation and negotiation.

Following the U.S. decision to deny a visa to Abutalebi, Iran said it had no immediate plans to name a new diplomat to the United Nations. Iran said it will instead pursue the issue through legal mechanisms at the U.N.

Iran called the U.S. decision "regrettable" and said it goes against international law and the right of sovereign states to name their U.N. representatives.

Abutalebi has been Iran's ambassador to Belgium, the European Union, Italy and Australia.

The Iranian hostage crisis led the United States and Iran to cut diplomatic relations.